Manipulations using a catheter, a guide wire and similar such medical instruments are often carried out in the field of interventional radiography and/or radiology on a human or animal patient, during which manipulations an accompanying imaging observation or monitoring is required and/or desired. To this end, an x-ray fluoroscopy for observing a relevant body region is carried out in parallel for instance.
It may be problematical here that large intensity differences may occur in the images produced in the case of recordings in the region of the heart for instance but also in the case of recordings in other body regions. The reason for this is that extremely x-ray-transparent regions and organs such as lungs for instance are also located in the image region radiated by means of the x-rays in addition to the intensely absorbent organs or tissue structures such as the heart or spinal column. The consequences thereof consist in very large dose differences within the relevant image region, thereby resulting if applicable in the image recording detector and the image system being overcontrolled.
The dose differences adversely affect the image quality, so that very dark and low contrast in addition to extremely light or even over-radiated regions are found. To counteract this problem, semi-transparent diaphragms are used since the transition between the regions with a high absorption and those with a low absorption is mostly very sharp and linear, said semi-transparent diaphragms being positioned over the less absorbent region. In this way, the dose difference relative to the highly absorbent region is reduced and the overall dynamic level of the image region is thus minimized.
The positioning of these semi-transparent diaphragms, which are used to control dose differences, is carried out manually. To this end, joysticks are used for instance, while a live observation of the manual positioning process is carried out on a monitor.
The manual positioning of the diaphragm requires a certain degree of experience and is comparatively complicated because each time a new positioning has to be carried out for instance, when individual parameters such as the table position, the angulation, a zoom stage or the position of the patient is changed. Accordingly, less time and/or attention is available to medical personal for medical actions or to technical personal for the actual image recording action, in other words the monitoring of a quality of the image recordings which is in all other cases sufficient. The operator, in this case a technician or scientist who operates a radiological facility, or also a doctor and/or medicine-related assistant who hereby deals with the implementation of the interventional method or any other medical measure, is solely responsible for the diaphragm positioning.